JP4991183B2 - Storage device, read data guarantee control device, and read data guarantee method - Google Patents

Description

  In the present invention, when a data reading error occurs in the vicinity of the track center of the storage medium, the offset is offset in the inner direction, which is the center direction of the storage medium, and the outer direction, which is the outer peripheral direction of the storage medium, to retry data reading The present invention relates to a storage device that guarantees read data read by a read retry process, a read data guarantee control device, and a read data guarantee method.

  In recent years, read heads of magnetic disk devices have become smaller than write heads in order to improve read speed and read reliability. This is because the read head has a poor S / N ratio (Signal to Noise ratio), so that the core of the head can only be reduced to a certain extent, whereas the read head has MR (Magneto Resistive), GMR (Giant). By using Magneto Resistive) and TMR (Turning Magneto Resistive), the core of the head can be made small without degrading the reading performance.

  By the way, the data written to the magnetic disk is ideally written along the track center line. However, the arm that supports the head vibrates slightly, and the write head also vibrates accordingly. Therefore, offset writing may occur in which the data is written with a deviation from the track center line.

  When new data is written on old data by such an offset write, both old data and new data may be readable in the vicinity of the track center line. This is because the offset of the offset write, that is, the deviation of the center line of the write data from the track center line, the old data is not completely overwritten by the new data, and a part of the old data remains readable. This is because new data is offset written.

  In this way, when new data is offset-written on old data, the end of the offset light may be positioned near the track center line, and when the read head tries to read data without offset, A read error may occur.

  As a coping method when such a reading error occurs, for example, Patent Document 1 discloses a method of reacquiring data by changing an offset amount according to a reading gain.

  Further, in Patent Document 2, when data can be recovered by offset read, a read error occurs, and after the data of the sector from which data was read by offset read and the sectors before and after that are saved, these data are saved. A magnetic disk device is disclosed in which data can be read without performing an offset read from the next time by rewriting the data in the original sector without offset.

JP 2004-134077 A JP 2001-118343 A

  However, in the prior art represented by Patent Documents 1 and 2, when new data is overwritten by offset write on old data, two types of data, old data and new data, are generated depending on the difference in offset amount. However, it is not guaranteed which data is reliable.

  Specifically, when new data is offset written in the outer circumferential direction of the magnetic disk, that is, the outer direction, on the old data written with an offset amount of 0 on the track center line, The data by the offset reading in the inner direction is old data, and the data by the offset reading in the outer direction is new data.

  In such a situation, it is impossible to determine which data is correct at the stage of first reading the data. Therefore, in the event of a data reading error on the track center line, how to guarantee the data read by performing offset reading has become an extremely important issue.

  The present invention has been made to solve the above problems (problems). When a data read error occurs on the track center line, offset read is performed as a read retry (retry read). It is an object of the present invention to provide a storage device that guarantees read data, a read data guarantee control device, and a read data guarantee method.

In order to solve the above-described problems and achieve the object, the present invention is directed to the inner direction that is the center direction of the storage medium and the outer peripheral direction of the storage medium when a data read error occurs near the track center of the storage medium. A storage device for guaranteeing the read data read by the offset read retry process for offsetting in the outer direction and retrying data reading, reading the inner offset data by the offset in the inner direction, and moving in the outer direction When the data reading unit that reads the outer offset data by the offset, the data comparison unit that compares the inner offset data and the outer offset data read by the data reading unit, and the comparison result by the data comparison unit match, Output control of the read data Comprising a data output control unit, and the data reading unit, wherein when the comparison result by the data comparing unit does not match, the same amount only stepwise offset each to offset and the outer direction to the inner direction The data output control unit has caused an error in reading one offset data by the offset reading by the data reading unit performed when the comparison result by the data comparison unit does not match In this case, when the data reading of the other offset is normally performed, the output control of the reading data by the other offset is performed .

Further, according to the present invention, when a data reading error occurs near the track center of the storage medium, the data is retried by offsetting in the inner direction that is the center direction of the storage medium and the outer direction that is the outer peripheral direction of the storage medium. A data guarantee control device for guaranteeing read data read by an offset read retry process, wherein the inner offset data read by the offset in the inner direction and the offset in the outer direction are read. When the comparison result by the data comparison unit comparing the outer offset data and the data comparison unit match, output control of the read data is performed, and when the comparison result by the data comparison unit does not match, the inner direction Offset amount and offset amount in the outer direction When an offset reading retry process is performed in which offset reading is performed with the same amount decreased step by step, when an error occurs in data reading of one offset in the offset reading retry process, the other offset When reading of data is successful, characterized by comprising a data output control unit for outputting control read data by said other offset, the.

Further, according to the present invention, when a data reading error occurs near the track center of the storage medium, the data is retried by offsetting in the inner direction that is the center direction of the storage medium and the outer direction that is the outer peripheral direction of the storage medium. A read data guarantee method for guaranteeing read data read by an offset read retry process, wherein inner offset data is read by an offset in the inner direction, and outer offset data is read by an offset in the outer direction . The first offset data reading step, the data comparison step for comparing the inner offset data read by the first data reading step and the outer offset data, and the comparison result by the data comparison step match the reading Export data A first data output control step of controlling, when said comparison result by the data comparing step does not match, the respective offset amount to the offset amount and the outer direction to the inner direction stepwise decreased by the same amount A second offset data reading step for performing offset reading, and when an error occurs in data reading for one offset in the second offset data reading step, the other offset data reading is normally performed. And a second data output control step for controlling the output of the read data by the offset .

  According to the present invention, since the read data is output when the comparison result between the read data by the inner offset and the read data by the outer offset matches, it is possible to guarantee the correctness of the read data by the offset and to output correct data. There is an effect that can be done.

  Further, according to the present invention, when the comparison result between the read data by the inner offset and the read data by the outer offset does not match, the offset amount in the inner direction and the offset amount in the outer direction are respectively decreased in steps by the same amount. The offset data is read, and when an error occurs in the data reading by one offset, if the data reading by the other offset is performed normally, the reading data by the other offset is output. There is an effect that correctness of data can be ensured and correct data can be output.

  Exemplary embodiments of a storage device, a read data guarantee control device, and a read data guarantee method according to the present invention will be described below in detail with reference to the accompanying drawings. In the following embodiments, the present invention is applied to a magnetic disk device connected to a host computer which is a computer system. However, the present invention is not limited to this, and can be widely applied to storage devices such as a magneto-optical disk device.

  First, problems in the conventional offset lead will be described. FIG. 1 is a diagram showing a problem in a conventional offset lead. As shown in the figure, the old write data is written on the magnetic disk so that the center line of the old write data coincides with the track center line of the magnetic disk. The new write data is overwritten on the old write data. Since the write core width of the old write data and the core width of the new write data are the same, the data width of the old write data matches the data width of the new write data. The new write data is offset-written in the “outer direction” (the outer circumferential direction of the magnetic disk) by the “offset amount” shown. This “offset amount” matches the “deviation” between the old write data center line and the new write data center line. The “offset amount” also coincides with the “deviation” between the boundary line on the “inner direction” side of the old write data and the boundary line on the “inner direction” side of the new write data.

  Here, the read core width of the read core is generally smaller than the write core width of the write core. Therefore, as shown in the figure, if the “offset amount” is smaller than the read core width, the old write data may be read by offset read in the track and sector where the new write data is offset-written. . That is, when the read core width is smaller than the “offset amount”, old write data may be erroneously read.

  The present invention has been made to solve such a problem. In particular, when data reading on the vicinity of the track center line has failed, when the read head is offset and re-reading is performed, the offset is set. This is done to ensure that the data read by the read is correct.

  Note that “if the“ offset amount ”is smaller than the read core width, the old write data is read by offset read in the track and sector where the new write data is offset-written”. At the inner and outer end portions of the write core, there is a non-readable portion that is not very readable but can be read by the read core. For this reason, if the “offset amount” is the same as the read core width, the end portion of the read core is applied to the unreadable portion, and in this case, a read error occurs.

  Next, features of the offset lead of the present invention will be described. FIG. 2 is a diagram showing feature points in the offset lead of the present invention. As shown in the figure, when a read error occurs near the track center line, the read core is offset and the data is read again, but the old write data center line that matches the old write data center line Then, the offset is offset by the same amount in each of the inner direction and the outer direction, and the data is read again. As described above, when the read core width is smaller than the offset amount, the read data at the time of offset read retry can be guaranteed by comparing the two data read by offsetting the same amount in the inner direction and the outer direction. It becomes possible.

  Although details will be described later, for example, as an example of guaranteeing the read data at the time of offset read retry, read data read by the offset read retry in the inner direction and read data read by the offset read retry in the outer direction If the two match, the read data can be determined to be correct, and this data is output to the host computer.

  Also, the read data read by the offset read retry in the inner direction is compared with the read data read by the offset read retry in the outer direction. If the two do not match, the read data is correct data. Therefore, error information is output to the host computer.

  Alternatively, the read data read by the offset read retry in the inner direction is compared with the read data read by the offset read retry in the outer direction, and if they do not match, the same amount is obtained in the inner direction and the outer direction. The offset amount is increased step by step and data read is retried, the data existing in the direction in which the read error has occurred first is set as incorrect data, and the other data is output as correct data to the host computer. This is based on the fact that the new write data can be read with a larger offset amount than the old write data because the new write data is offset-written.

  Alternatively, the read data read by the offset read retry in the inner direction is compared with the read data read by the offset read retry in the outer direction, and if they do not match, the offset in the inner direction and the outer direction is set. The amount is decreased step by step by the same amount, and data reading is retried. The data existing in the direction in which the reading error has occurred is regarded as incorrect data, and the other data is output as correct data to the host computer. However, on the assumption that the new write data is offset-written so that the offset amount does not exceed (write core width / 2), the new write data is read even with a smaller offset amount than the old write data. Based on what is possible.

  As described above, when a read error occurs in the vicinity of the track center, both the inner offset read and the outer offset read are performed, and the process to be performed next is determined based on the comparison result and the verification result. Since the read data is not determined based only on the read result of either the inner offset read or the outer offset read, even if the data is offset written and different data can be read in the same sector of the same track, the read is not performed. It is possible to guarantee the validity of data.

  Next, a first example of processing when a read error occurs near the track center will be described. FIG. 3 is a diagram (part 1) illustrating an overview of processing when a read error occurs near the track center. As shown in the figure, there is a read error area where a data read error occurs in the vicinity below the track center, and (1) a read error occurs because the read core tries to read this read error area. (2) If both of the offset readings of the same offset amount in the inner direction and the outer direction have succeeded and the read data of both of them are the read data 1, the read data 1 is regarded as correct data. Send to host computer.

  Next, a second example of processing when a read error occurs near the track center will be described. FIG. 4 is a diagram (part 2) illustrating an overview of processing when a read error occurs in the vicinity of the track center. As shown in the figure, there is a read error area where a data read error occurs in the vicinity below the track center, and (1) a read error occurs because the read core tries to read this read error area. (2) Both offset reads of the same offset amount in the inner direction (the center direction of the magnetic disk, the downward direction in the figure) and the outer direction (the outer peripheral direction of the magnetic disk, the upward direction in the figure) have succeeded. Read data is read data 1 and read data 2, which do not match. (3) Here, the offset amount of the inner offset read and the outer offset read is further decreased step by step by the same amount, and the data read retry is continued. This is referred to as a reduced offset retry read.

  (4) As a result, if any of the read errors occurs first (in the figure, the offset read in the inner direction is the error first), the offset read data that did not result in the read error (read data in the figure) 1) is sent to the host computer as correct data.

  Next, a third example of processing when a read error occurs near the track center will be described. FIG. 5 is a diagram (part 3) illustrating an overview of processing when a read error occurs near the track center. As shown in the figure, there is a read error area where a data read error occurs near the center of the track. (1) A read error occurs because the read core attempts to read this read error area. (2) Then, offset reads of the same offset amount in the inner direction and the outer direction were performed, but only one of the offset reads succeeded (in the figure, only the offset read in the outer direction succeeded). Data 1 is sent as correct data to the host computer.

  Next, a fourth example of processing when a read error occurs near the track center will be described. FIG. 6 is a diagram (part 4) illustrating an outline of processing when a read error occurs in the vicinity of the track center. As shown in the figure, there is a read error area where a data read error occurs near the center of the track. (1) A read error occurs because the read core attempts to read this read error area. (2) Then, only one of the offset reads of the same offset amount in the inner direction and the outer direction succeeds (only the offset read in the outer direction succeeds in the figure). (3) Further, the offset amount of the inner offset lead and the outer offset lead is increased step by step by the same amount, and the data reading is continuously retried. As a result, when only one of them (only the offset reading in the outer direction in the figure) still succeeds, the read data 1 that has been successfully read is sent to the host computer as correct data. This is referred to as incremental offset retry read.

  Next, a fifth example of processing when a read error occurs near the track center will be described. FIG. 7 is a diagram (No. 5) showing an outline of processing when a read error occurs near the track center. As shown in the figure, there is a read error area where a data read error occurs in the vicinity below the track center, and (1) a read error occurs because the read core tries to read this read error area. (2) Then, only one of the offset reads of the same offset amount in the inner direction and the outer direction succeeds (only the offset read in the outer direction succeeds in the figure). (3) Further, the offset amount of the inner offset lead and the outer offset lead is increased step by step by the same amount, and the data reading is continuously retried. As a result, both offset reads of the same offset amount in the inner direction and the outer direction are successful, and the read data does not match the read data 1 and the read data 2. In this case, error information is sent to the host computer.

  Next, the configuration of the hard disk controller included in the magnetic disk of the embodiment will be described. FIG. 8 is a functional block diagram showing the configuration of the hard disk controller. As shown in the figure, the hard disk controller 100 includes an offset retry control unit 101, an offset retry data verification unit 102, a head drive control unit 103, a control parameter interface unit 104, a disk interface unit 105, an ECC (Error Correcting code) processing unit 106 and host interface unit 107. The offset read retry control unit 101 and the offset retry data verification unit 102 are configured by a firmware program of an MCU (Microcontroller Unit).

  When the read data read from the magnetic disk and transferred to the disk interface unit 105, the ECC processing unit 106, and the offset retry data verification unit 102 is information indicating an error, the offset retry control unit 101 reads the information. An instruction is output to the head drive control unit 103 so as to perform offset retry reading in the direction and the outer direction.

  Further, when the read data by the offset retry read in the inner direction and the outer direction do not match or one of them is a read error, the head drive control unit 103 is offset by the same amount in the inner direction and the outer direction. An instruction to continue offset reading by changing (increasing or decreasing) step by step is output.

  The offset retry data verification unit 102 performs processing for verifying read data read from the magnetic disk delivered from the disk interface 105 via the ECC processing unit 106. Specifically, it is verified whether both the read data by the offset read in the inner direction and the read data by the offset read in the outer direction are successfully read and matched, or one of the offset reads is successful. Whether or not one offset read has failed is recognized, read data that has succeeded in offset reading is handled as valid data, and if both offset reads fail, an error is recognized. The offset retry data verification unit 102 branches the process in accordance with an externally set control parameter referred to via the control parameter interface unit 104.

  The offset retry control unit 101 controls the output of read data based on the verification result of the offset retry data verification unit 102 and causes the host interface unit 107 to output the read data to the host computer.

  The head drive control unit 103 performs drive control of the support arm of the magnetic head based on an instruction from the offset retry control unit 101. In general, the drive control of the support arm of the magnetic head is performed according to the read / write position information of the data specified based on the servo information written on the magnetic disk.

  The control parameter interface unit 104 is an interface that receives selection information of a processing method at the time of offset retry set from the outside of the magnetic disk device. As a specific example of a method for accepting processing method selection information at the time of offset retry from the outside via the control parameter interface unit 104, a mode parameter of SCSI (Small Computer System Interface) or a dip switch provided in the magnetic disk device is used. There are ways to do it. The selection information of the processing method at the time of offset retry set from the outside of the magnetic disk device is a control parameter referred to at the time of offset read retry processing in the hard disk controller 100 of the magnetic disk, as will be described later. Details of this control parameter will be described later.

  The disk interface unit 105 transfers information read from the magnetic disk head (read core) to the ECC processing unit 106, and outputs the data transferred from the ECC processing unit 106 to the magnetic disk head (write core) to generate magnetism. It is an interface for writing to a disk.

  The ECC processing unit 106 performs a process of ECC-coding the write data to the magnetic disk and ECC-decoding the read data from the magnetic disk. Furthermore, the ECC processing unit 106 reads data that has been successfully read in one of the inner direction and the outer direction by offset retry into the same sector of the same track in accordance with a control parameter referenced from the outside via the control parameter interface unit 104. Perform overwriting process. This makes it possible to read correct data without performing an offset read retry thereafter. In addition, when the ECC processing unit 106 outputs a read error in accordance with a control parameter referred to from the outside via the control parameter interface unit 104, the ECC processing unit 106 converts data that cannot be corrected by ECC into the same track. Performs processing to overwrite the same sector. As a result, it is possible to prevent an error from being always output in the corresponding sector of the track and reading erroneous data.

  The host interface unit 107 is an interface that receives data to be written to the magnetic disk from the host computer and delivers it to the ECC processing unit 106, and receives data read from the magnetic disk from the ECC processing unit 106 and delivers it to the host computer. .

  Next, the setting contents of the 4-bit parameter relating to the offset retry method will be described. FIG. 9 is a diagram showing the setting contents of the setting contents of the 4-bit parameter regarding the offset retry method. The 4-bit parameter is a control parameter set from the outside of the magnetic disk device described above. As shown in the figure, the 4-bit parameter is composed of 4 bits of bit0 to bit3. By providing this 4-bit parameter, it is possible to freely set the branching of processing according to the operation mode of the host computer and the magnetic disk device, and to perform necessary processing as necessary, thereby improving processing efficiency. Can be achieved.

  Bit 0 is information about verification permission when different data has been successfully read in both the inner and outer offset reads. When bit 0 is “0”, the setting content is “error report without verification”. That is, when different data is successfully read in both the inner and outer offset reads, the error information is set to be output as an error unconditionally. When bit 0 is “1”, the setting content is “Verify which is valid data”. That is, when different data has been successfully read in both the inner and outer offset reads, it is set to verify which read data is correct and valid data. As a result, even if different data is read by the offset retry read in the inner direction and the outer direction, it is possible to further guarantee the correctness of the data by verifying which data is valid. .

  Bit 1 is information on verification permission when data has been successfully read in either the inner direction or the outer direction offset read. When bit 1 is “0”, the setting content is “data transmission without verification (normal end)”. That is, when the data is successfully read by either the inner direction or the outer direction offset read, the data that has been successfully read is unconditionally output as correct data. When bit 1 is “1”, the setting content is “Verify whether other data exists in the same track”. That is, when data has been successfully read in either the inner direction or the outer direction offset read, it is set to verify whether other data does not exist in the same track by performing a reduced offset retry read or an increased offset retry read. Is. As a result, even if the offset retry read is successful once, it is verified whether or not the data that has been successfully read is truly correct data, and the validity of the data can be further ensured.

  Bit 2 is information on data destruction permission at the time of error. When bit2 is “0”, the setting content is “not overwritten at the time of error”. That is, when data read error information is output, it is set that the data in the sector of the track is not destroyed by data that cannot be ECC corrected. When bit 2 is “1”, the setting content is “overwrite with data unreadable at the time of error”. That is, when data read error information is output, the data of the sector in the track is overwritten with data that cannot be corrected by ECC and destroyed. As a result, it is possible to prevent data from being erroneously read by retry read thereafter.

  Bit 3 is information on overwriting permission at the time of data transmission. When bit 3 is “0”, the setting content is “not overwritten when read normally”. That is, when the data reading is successful and the data is output, the data of the sector in the track is set not to be overwritten with the read data. When bit 3 is “1”, the setting content is “overwrite with transmitted data”. That is, it is set to overwrite the data of the sector of the track with the data that has been successfully read. As a result, data is always read normally even in retry reading.

  Next, an offset read retry processing procedure executed in the hard disk controller 100 shown in FIG. 8 will be described. FIG. 10 is a flowchart showing an offset read retry processing procedure executed in the hard disk controller 100 shown in FIG. As shown in the figure, first, an inner offset lead and an outer offset lead are performed (step S101). Subsequently, it is determined whether or not an error has occurred in offset reading (step S102). If it is determined that an error has occurred (Yes in step S102), the process proceeds to step S103, and no error has occurred. If it is determined (No at Step S102), the process proceeds to Step S105.

  In step S103, it is determined whether both the inner offset lead and the outer offset lead are in error. If both are determined to be errors (Yes in step S103), retry continuation by another method or an error is reported (step S104). When step S104 ends, the offset read retry process ends. On the other hand, if both are not determined to be errors (No at step S103), the process proceeds to step S107.

  On the other hand, in step S105, it is determined whether or not the read data of the inner offset lead and the outer offset read match. If it is determined that they match (Yes in step S105), the matching data is sent to the host computer. (Step S106), and the offset read retry process ends. If it is not determined that they match (No at Step S105), the process proceeds to Step S116.

  In step S107, it is determined whether or not bit1 is set to “1”. If bit1 is set to “1” (Yes in step S107), the read data is defined as RD_DATA and temporarily stored (step S107). S108) When the setting of bit1 is not “1” (No at Step S107), the read data is transmitted to the host computer (Step S113). When step S113 ends, the offset read retry process ends.

  In step S109 following step S108, the offset amount is increased, and it is determined whether the offset has reached a predetermined specified value (step S110). When it is determined that the offset has reached a predetermined specified value (Yes at Step S110), RD_DATA is transmitted to the host computer (Step S114), the offset read retry process is completed, and the offset has reached the end of the track. If not determined (No at Step S110), the inner offset read and the outer offset read are performed again (Step S111).

  Next, it is determined whether or not the read result of the inner offset read and the outer offset read is equal to RD_DATA or one of them is a read error (step S112). If step S112 is affirmative, the process proceeds to step S109. If S112 is negative, an error is reported (step S115). When step S115 ends, the offset read retry process ends.

  On the other hand, in step S116 subsequent to the case where step S105 is negative, it is determined whether or not the value of bit0 is “1”. When the value of bit0 is determined to be “1” (Yes at Step S116), the process proceeds to Step S117, and when the value of bit0 is not determined to be “1” (No at Step S116), an error is reported ( Step S120), the offset read retry process ends.

  In step S117, the offset amount is decreased, and the inner offset read and the outer offset read are performed again (step S118). Subsequently, it is determined whether or not the inner offset lead or the outer offset lead is an error (step S119). If it is determined that the inner offset lead or the outer offset lead is an error (Yes in step S119), the process proceeds to step S117. If the inner offset read or the outer offset read is not determined to be an error (No at step S119), the read data is transmitted to the host computer (step S121), and the offset read retry process is terminated.

  According to the present embodiment, when different data can be read in the same track by offset read (inner offset read and outer offset read) due to an increase in the difference between the write core width and the read core width, erroneous data is hosted. It can be prevented from being sent to a computer and data can be guaranteed to improve reliability.

  More specifically, when a read error occurs, offset reading is performed on the inner side and the outer side of the track, and the respective data is compared and verified, whereby erroneous data is recorded in the track and sector in which the data is offset written. Transmission to the host computer can be prevented.

  As mentioned above, although the Example of this invention was described, this invention is not limited to this, In the range of the technical idea described in the claim, even if it implements in a various different Example, it is. It ’s good. Moreover, the effect described in the Example is not limited to this.

(Supplementary Note 1) When a data reading error occurs near the track center of the storage medium, an offset is set to retry the data reading by offsetting in the inner direction that is the center direction of the storage medium and the outer direction that is the outer peripheral direction of the storage medium. A storage device that guarantees read data read by a read retry process,
A data reading unit that reads inner offset data by an offset in the inner direction and reads outer offset data by an offset in the outer direction;
A data comparison unit for comparing the inner offset data and the outer offset data read by the data reading unit;
And a data output control unit that controls the output of the read data when the comparison results by the data comparison unit match.

(Appendix 2) The data output control unit outputs the data that has been successfully read when the data reading unit has successfully read either the inner offset data or the outer offset data. The storage device according to appendix 1.

(Supplementary Note 3) When the comparison result by the data comparison unit does not match, the data reading unit offsets the offset amount in the inner direction and the offset amount in the outer direction by the same amount in steps. Read
The data output control unit, when an error occurs in data reading of one offset by the data reading unit, when the data reading of the other offset is normally performed, performs output control of reading data by the other offset The storage device according to appendix 1, wherein:

(Supplementary Note 4) When the data reading unit succeeds in reading either the inner offset data or the outer offset data, the same amount of the offset amount in the inner direction and the offset amount in the outer direction are used. Incrementally read the offset,
The data output control unit outputs the read data of the other offset when the data reading of the other offset is normally performed when an error occurs in the data reading of the one offset by the data reading unit. The storage device according to attachment 1, wherein the storage device is characterized.

(Appendix 5) When read data that has been successfully read by either the inner offset data or the outer offset data is output by the data reading unit, the read data is overwritten on the entire track and sector that have been successfully read. The storage device according to appendix 3 or 4, further comprising a read data overwriting unit.

(Supplementary note 6) The storage device according to supplementary note 1, wherein the data output control unit outputs read error information when a comparison result by the data comparison unit does not match.

(Supplementary note 7) When the data reading unit succeeds in reading either the inner offset data or the outer offset data by the data reading unit, the offset amount in the inner direction and the offset amount in the outer direction Perform offset reading by increasing each by the same amount step by step,
The data output control unit outputs read error information when the data reading unit succeeds in reading data with both offsets and the data comparing unit determines that the read data with both offsets do not match. The storage device according to attachment 1, wherein

(Supplementary note 8) When the read error information is output by the data output control unit, error correction that overwrites uncorrectable data by ECC (Error Correcting Code) over the entire track and sector where the read error has occurred The storage device according to appendix 6 or 7, further comprising an impossible data overwrite unit.

(Supplementary Note 9) If the comparison result by the data comparison unit does not match, read error information is output, or the offset amount in the inner direction and the offset amount in the outer direction are decreased stepwise by the same amount. When an error occurs in reading data by one offset and data reading by the other offset is normally performed, the first selection is made to select whether to output the read data by the other offset. The storage device according to appendix 1, further comprising a selection unit.

(Supplementary Note 10) When the data reading unit succeeds in reading either the inner offset data or the outer offset data, the data that has been successfully read is output, or the offset amount in the inner direction and the outer The offset reading in the direction is decreased by the same amount step by step to perform offset reading, and when an error occurs in data reading by one offset, if the data reading by the other offset is performed normally, the other offset The storage device according to appendix 1, further comprising: a second selection unit that selects whether to output read data based on the offset.

(Supplementary Note 11) When read data that has been successfully read by either the inner offset data or the outer offset data is output by the data reading unit, the read data is overwritten on the entire track and sector that have been successfully read. The storage device according to appendix 3 or 4, further comprising a third selection unit that selects whether or not to perform.

(Supplementary Note 12) Whether or not data that cannot be corrected by ECC (Error Correcting Code) is overwritten on the entire track and sector where the read error occurs when the data output control unit outputs read error information. The storage device according to appendix 6 or 7, further comprising: a fourth selection unit that selects.

(Additional remark 13) When a data reading error occurs near the track center of the storage medium, an offset is made to retry the data reading by offsetting in the inner direction that is the center direction of the storage medium and the outer direction that is the outer peripheral direction of the storage medium. A data guarantee control device for guaranteeing read data read by a read retry process,
A data comparison unit for comparing the inner offset data read by the offset in the inner direction and the outer offset data read by the offset in the outer direction;
And a data output control unit that controls the output of the read data when the comparison results by the data comparison unit match.

(Supplementary Note 14) The data output control unit outputs the data that has been successfully read when the data has been successfully read by either the data reading by the offset in the inner direction or the data reading by the offset in the outer direction. 14. The read data guarantee control device according to appendix 13, wherein

(Supplementary Note 15) When the comparison result by the data comparison unit does not match, the data output control unit reduces the offset amount in the inner direction and the offset amount in the outer direction by the same amount in steps. Supplementary note 13 is characterized in that, when an error occurs in data reading by one offset when reading an offset, if the data reading by the other offset is normally performed, the read data by the other offset is output. Read data guarantee controller.

(Supplementary Note 16) When the data output control unit succeeds in data reading by either the data reading by the offset in the inner direction or the data reading by the offset in the outer direction, the offset amount in the inner direction and At the time of offset reading performed by increasing each offset amount in the outer direction by the same amount step by step, when an error occurs in data reading by one offset, data reading by the other offset is normally performed. 14. The read data guarantee control device according to appendix 13, wherein the read data with the other offset is output.

(Supplementary note 17) The read data guarantee control device according to supplementary note 13, wherein the data output control unit outputs read error information when a comparison result by the data comparison unit does not match.

(Supplementary Note 18) The data output control unit can detect the offset amount in the inner direction when the data reading is successful by either the data reading by the offset in the inner direction or the data reading by the offset in the outer direction. Read error information when data reading by both offsets succeeds and the data read by both offsets do not match at the time of offset reading performed by incrementally increasing the respective offset amounts in the outer direction. The read data guarantee control device according to appendix 13, characterized in that:

(Supplementary Note 19) If the comparison result by the data comparison unit does not match, read error information is output, or the offset amount in the inner direction and the offset amount in the outer direction are decreased stepwise by the same amount. When an error occurs in reading data by one offset and data reading by the other offset is normally performed, the first selection is made to select whether to output the read data by the other offset. 14. The read data assurance control device according to appendix 13, further comprising a selection unit.

(Supplementary note 20) When a data reading error occurs near the track center of the storage medium, an offset is set to retry the data reading by offsetting in the inner direction that is the center direction of the storage medium and the outer direction that is the outer peripheral direction of the storage medium A read data guarantee method for guaranteeing read data read by a read retry process,
An offset data reading step of reading inner offset data by an offset in the inner direction and reading outer offset data by an offset in the outer direction;
A data comparison step of comparing the inner offset data and the outer offset data read by the data reading step;
And a data output control step of controlling the output of the read data when the comparison results in the data comparison step match.

  The present invention is useful when it is desired to guarantee the data read in the offset read retry of the storage medium. In particular, new data is offset-written to old data, and both old data and new data are offset-read. This is effective when it is desired to guarantee which read data can be handled as valid data when the data can be read.

It is a figure which shows the problem in the conventional offset lead. It is a figure which shows the characteristic shop in the offset lead of this invention. FIG. 10 is a diagram (part 1) illustrating an overview of processing when a read error occurs in the vicinity of a track center; FIG. 11 is a diagram (part 2) illustrating an overview of a process when a read error occurs in the vicinity of a track center. FIG. 11 is a diagram (part 3) illustrating an overview of a process when a read error occurs in the vicinity of a track center; FIG. 14 is a diagram (No. 4) illustrating an overview of processing when a read error occurs near the track center; FIG. 11 is a diagram (No. 5) illustrating an overview of a process when a read error occurs in the vicinity of a track center. It is a functional block diagram which shows the structure of a hard disk controller. It is a figure which shows the setting content of the 4-bit parameter regarding an offset retry method. It is a flowchart which shows an offset read retry process sequence.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Hard disk controller 101 Offset retry control part 102 Offset retry data verification part 103 Head drive control part 104 Control parameter interface part 105 Disk interface part 106 ECC processing part 107 Host interface part

Claims (3)

Offset reading retry processing for retrying data reading with an offset in the inner direction which is the center direction of the storage medium and the outer direction which is the outer peripheral direction of the storage medium when a data reading error occurs near the track center of the storage medium A storage device for guaranteeing the read data read by
A data reading unit that reads inner offset data by an offset in the inner direction and reads outer offset data by an offset in the outer direction;
A data comparison unit for comparing the inner offset data and the outer offset data read by the data reading unit;
A data output control unit that controls the output of the read data when the comparison result by the data comparison unit matches,
When the comparison result by the data comparison unit does not match, the data reading unit performs offset reading by gradually reducing the offset amount in the inner direction and the offset amount in the outer direction by the same amount,
The data output control unit reads the data of the other offset when an error occurs in the data reading of one offset by the offset reading by the data reading unit performed when the comparison result by the data comparison unit does not match. If normally performed, output control of read data by the other offset,
A storage device. Offset reading retry processing for retrying data reading with an offset in the inner direction which is the center direction of the storage medium and the outer direction which is the outer peripheral direction of the storage medium when a data reading error occurs near the track center of the storage medium A data guarantee control device for guaranteeing read data read by
A data comparison unit for comparing the inner offset data read by the offset in the inner direction and the outer offset data read by the offset in the outer direction;
When the comparison result by the data comparison unit matches, output control of the read data, and when the comparison result by the data comparison unit does not match, the offset amount in the inner direction and the offset amount in the outer direction, respectively When an offset reading retry process is performed in which offset reading is performed with the same amount decreased step by step, when an error occurs in the data reading of one offset in the offset reading retry process, the offset of the other offset When data reading is normally performed, a data output control unit that controls output of read data by the other offset,
A data assurance control device comprising: Offset reading retry processing for retrying data reading with an offset in the inner direction which is the center direction of the storage medium and the outer direction which is the outer peripheral direction of the storage medium when a data reading error occurs near the track center of the storage medium A read data guarantee method for guaranteeing read data read by
A first offset data reading step of reading inner offset data by an offset in the inner direction and reading outer offset data by an offset in the outer direction;
A data comparison step of comparing the inner offset data and the outer offset data read by the first data reading step;
A first data output control step for controlling the output of the read data when the comparison results in the data comparison step match;
A second offset data reading step of performing offset reading by gradually reducing the offset amount in the inner direction and the offset amount in the outer direction by the same amount when the comparison result in the data comparison step does not match When,
If an error occurs in reading one offset data in the second offset data reading step and the other offset data is normally read, the second data for controlling the output of the read data by the other offset Output control process;
A method for guaranteeing read data, comprising:

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